1. Field of the Invention
This invention relates to an apparatus for forming stacks from consecutively conveyed, flat workpieces, preferably bags, comprising a ram which is movable up and down and serves to force the workpieces from a plane of conveyance onto a stacking plate or onto a stack formed on said stacking plate, wherein the stacking plate is adapted to be lifted and to be lowered to an extent depending on the increasing height of the stack.
2. Description of the Prior Art
In an apparatus of that kind which is known from U.S. Pat. No. 3,810,420, bags which have been severed from a continuous tubular film and in a preceding working step have been provided with bottom seam welds are forced by a ram onto a pivoted stacking plate, which is adapted to be lowered against spring force and which is continually forced down by the ram to such an extent that the trailing end portions of the deposited bags extend below a step, which protrudes over the stacking plate. When the ram has been lifted from the stacking plate, the spring which biases the stacking plate raises the stacking plate so that the trailing edge portions of the bags are forced against the underside of the step. In the known apparatus the spring which biases the stacking plate is increasingly compressed as the height of the stack increases and for this reason the ram is required to exert a correspondingly increasing force. In the forming of high stacks from workpieces consisting of delicate materials, the ram may possibly damage at least the last bags of a stack.